Introduction
The Alctron DI-120 is a versatile two-channel passive direct box designed to convert unbalanced, high-impedance instrument signals into balanced, low-impedance signals suitable for professional audio equipment. This device is essential for connecting instruments like keyboards, acoustic guitars, and electric guitars directly to mixing consoles or audio interfaces, especially in live performance or studio recording environments where long cable runs are common.
Its passive design means it does not require external power, making it reliable and easy to use. The DI-120 features dual inputs, link outputs for connecting to stage amplifiers, selectable pad settings to handle various signal levels, and a ground lift switch for each channel to eliminate hum and noise.
Package Contents
- Alctron DI-120 Passive Direct Box
- User Manual (this document)
Product Overview
The Alctron DI-120 features a robust metal casing with rubber feet for stability and protection. It includes two independent channels, each with its own input, link output, balanced output, PAD switch, and ground lift switch.
Input Side Features
- INPUT (1/4" Phone Jack, Unbalanced): Connect your instrument (e.g., guitar, keyboard) here.
- PAD Switch (0dB, -20dB, -40dB): Attenuates the input signal. Use for high-output instruments to prevent clipping.
- LINK Output (1/4" Phone Jack, Unbalanced): Provides a direct, unprocessed signal to connect to a stage amplifier or other instrument-level device.
Output Side Features
- BALANCED IN/OUT (XLR Connector, Balanced): Connect this output to a mixing console's microphone input or an audio interface.
- GROUND LIFT Switch: Disconnects the ground connection between the input and output to eliminate hum caused by ground loops.
Setup and Connections
Follow these steps to properly set up your Alctron DI-120:
- Connect Instrument to Input: Plug your instrument (e.g., electric guitar, bass, keyboard) into one of the 1/4" INPUT jacks on the DI-120 using a standard instrument cable.
- Connect to Amplifier (Optional): If you wish to use a stage amplifier, connect the corresponding 1/4" LINK Output to your amplifier's input. This allows you to monitor your sound on stage while sending a separate signal to the mixer.
- Connect to Mixer/Audio Interface: Use an XLR cable to connect the BALANCED IN/OUT XLR connector to a microphone input on your mixing console or audio interface.
- Power On: Since the DI-120 is a passive unit, it does not require external power. It will function as soon as signals are connected.
Operating Instructions
Using the PAD Switch
The PAD switch allows you to attenuate the input signal by 0dB, -20dB, or -40dB. This is crucial for preventing signal clipping when connecting high-output instruments or line-level sources.
- 0dB: No attenuation. Use for instruments with lower output levels.
- -20dB: Reduces the signal by 20 decibels. Suitable for most active guitars, keyboards, or line-level signals.
- -40dB: Reduces the signal by 40 decibels. Use for very hot signals, such as speaker outputs from amplifiers (ensure the amplifier's output is suitable for a DI box).
Always start with the 0dB setting and switch to -20dB or -40dB if you hear distortion or if the input meter on your mixer/interface shows clipping.
Using the GROUND LIFT Switch
The GROUND LIFT switch helps eliminate hum and buzz caused by ground loops. A ground loop occurs when there are multiple ground paths in an audio system, creating unwanted noise.
- ON (Ground Connected): This is the default position. The ground connection between the input and output is maintained.
- OFF (Ground Lifted): This position disconnects the ground path between the input and output. If you hear a hum or buzz in your audio, try flipping this switch to the OFF position. If the hum disappears, leave it in the OFF position.
Use the ground lift only when necessary, as it can sometimes introduce other issues if not properly managed in a complex system.
Maintenance
To ensure the longevity and optimal performance of your Alctron DI-120, follow these maintenance guidelines:
- Cleaning: Wipe the unit with a soft, dry cloth. Do not use abrasive cleaners, solvents, or waxes.
- Storage: Store the DI box in a cool, dry place away from direct sunlight and extreme temperatures.
- Handling: Avoid dropping the unit or subjecting it to strong impacts. While robust, excessive force can damage internal components.
- Cables: Always use high-quality cables and ensure they are in good condition. Faulty cables can introduce noise or signal loss.
Troubleshooting
If you encounter issues with your DI-120, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Hum or Buzzing Noise | Ground loop | Engage the GROUND LIFT switch (OFF position). |
| Distorted or Clipped Signal | Input signal is too hot | Engage the PAD switch to -20dB or -40dB to attenuate the signal. |
| No Sound Output | Incorrect connections, faulty cables, or incorrect PAD setting | Check all cable connections. Ensure cables are not damaged. Verify the PAD switch is not set too high for a low-output instrument. Check mixer/interface input settings. |
| Weak or Low Signal | PAD switch set too high | Ensure the PAD switch is set to 0dB for instruments with lower output levels. |
Specifications
| Feature | Specification |
|---|---|
| Frequency Response | 10Hz - 25KHz |
| Noise Level (22Hz - 22KHz, Input Shorted) | -100dBu |
| Input Connectors | Two 1/4” Phone Jacks, Unbalanced |
| Output Connectors | Two XLR Connectors, Balanced |
| Link Output Connectors | Two 1/4” Phone Jacks, Unbalanced |
| PAD Switch Settings | 0dB, -20dB, -40dB (two switches) |
| Ground Lift | Two independent switches |
| Dimensions (LxWxH) | 135 x 114 x 47.5 mm |
| Weight | Not specified |
| Additional Features | Rubber Feet Pad |
User Tips
- Phantom Power: As a passive DI box, the Alctron DI-120 inherently isolates the input from phantom power. This means you can safely connect instruments without worrying about phantom power damaging them.
- Headroom for Hot Signals: The DI-120's PAD switches (0dB, -20dB, -40dB) provide ample headroom for various signal levels. For high-output devices like certain synthesizers or guitar amp modelers (e.g., Bomm MS-3 / ToneX), utilize the -20dB or -40dB pad settings to ensure a clean, undistorted signal to your mixer or interface.
- Cable Management: Keep instrument and XLR cables organized and away from power cables to minimize interference.
Warranty and Support
For warranty information and technical support, please refer to the documentation provided by your retailer or contact the manufacturer directly. Keep your proof of purchase for any warranty claims.
